Releasable adhesives for attachment of substrates and joints

Abstract

A Joint between a first and a second assembly part has adjoining side walls, which may be tightly joined together by means of a sealing bed provided with a removable adhesive sealant, The first side wall has a first sealing surface attached thereto, the first side wall in the joined state running at a distance approximately parallel to a second sealing surface attached to a second side wall, and both of the sealing surfaces form the sealing bed with a level running direction, directed away from the side walls, in whose extension the adhesive sealing material can be withdrawn. A method for producing a joint between a first assembly part and a second assembly part, where a removable adhesive sealant is applied in the liquid state to a sealing bed area of the first assembly part, and both of the assembly parts are joined together. To remove said adhesive sealant, the same is grasped at a free end and, in an extension of a level running direction of the sealing bed, directed away from both assembly parts, is withdrawn essentially residue-free from the sealing bed.

1 . A hot-melt adhesive comprising a non-pressure-sensitive adhesive that is fluid at application temperatures and that is removable, residue-free, by peeling at small peel angles, wherein the improvement comprises that said adhesive contains additives selected from the group consisting of fillers, stabilizers, dyes, carbon black, and moisture absorbents, said adhesive also containing the following: 
 a) thermoplastic elastomers that may be grafted,    b) grafted poly-α-olefins,    c) polyisobutylene or a softening oil,    d) adhesive resin, and    e) end block resin.    
     
     
         2 . The adhesive according to  claim 1 , wherein the thermoplastic elastomers are styrenes selected from the group consisting of SBS, SIS, SEBS, SEPS, and block polystyrene-(block poly(ethylene-butylene)), block polystyrene-(block poly(ethylene-butylene)) having 1 to 10 block styrene units per molecule, which optionally are modified with block polyisoprene or block butadiene units; elastomer alloys selected from the group consisting of EPDMIPP, NR/PP, EVA/PVDC, and NBR/PP, polyurethane, polyether esters, or polyamides.  
     
     
         3 . The adhesive according to  claim 1 , wherein the poly-α-olefins are at least partially grafted, and the poly-α-olefins are selected from amorphous poly-α-olefins, monopolymers, copolymers, or terpolymers of the monomers ethylene, propylene, 1-butene, 1-pentene, and 1-hexene, or from a poly-α-olefin of the general formula (I):  
       
         
           
           
               
               
           
         
       
       where 
 m=0 to 15, and  
 n=5 to 50,000.  
 
     
     
         4 . The adhesive according to  claim 3 , wherein the poly-α-olefins are semicrystalline, and the poly-α-olefins comprise at least one of polyethylene, polypropylene, or poly-1-butene, which have high tacticity in the crystalline regions.  
     
     
         5 . The adhesive according to  claim 3  or  4 , wherein the poly-α-olefins are randomly grafted with olefinically unsaturated compounds, which in particular are selected from maleic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, and compounds of the general formula (II):  
       
         
           
           
               
               
           
         
       
       where 
 R 1  represents the following groups:  
                     where 
 Z is hydrogen, a methyl group, or a phenyl group, and  
 X is —(—CH 2 —)— or  
                     
 where  
   
 Y is a hydrolyzable group,  
 m 0,1, or 2,  
 n is 0, 1, or 2, and  
 l is l, 2, 3, 4, 5, or 6; or  
                     where 
 k is 0, 1, or 2,  
   
 R 2  is hydrogen or methyl,  
 R 3  is an R 1  group, hydrogen, or methyl, and  
 R 4  is hydrogen or methyl.  
 
     
     
         6 . An adhesive according to  claim 1 , wherein the quantity of grafted poly-α-olefins is 0 to 100% by weight, relative to the total content of poly-α-olefins.  
     
     
         7 . The adhesive according to  claim 1 , wherein the thermoplastic elastomers are randomly grafted with olefinically unsaturated compounds that are selected from maleic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, or compounds of the general formula (II):  
       
         
           
           
               
               
           
         
       
       where 
 R 1  represents the following groups:  
                     where 
 Z is hydrogen, a methyl group, or a phenyl group, and  
 X is —(—CH 2 —) 1 — or  
                     
 where  
   
 Y is a hydrolyzable group,  
 m 0,1, or 2,  
 n is 0, 1, or 2, and  
 l is 1, 2, 3, 4, 5, or 6; or  
                     
 where 
 k is 0, 1, or 2,  
 
 R 2  is hydrogen or methyl,  
 R 3  is an R 1  group, hydrogen, or methyl, and  
 R 4  is hydrogen or methyl.  
 
     
     
         8 . The adhesive according to  claim 1 , wherein the percentage of grafted thermoplastic elastomers, relative to the total content of the thermoplastic elastomers, is 0 to 1 00% by weight.  
     
     
         9 . The adhesive according to  claim 1 , wherein the adhesive resins are selected from polymeric monomers of the petrochemical C 5  to C 9  distillation fractions, which are not hydrated partially hydrated, or completely hydrated, natural rosin resins, modified natural rosin resins, terpene resins, polyterpene resins of β-pinene, α-pinene, and/or δ-limonene; resins obtained by copolymerization of terpene with monomers from the C 5  to C 9  fraction from petroleum distillation, or terpene-phenol resins.  
     
     
         10 . The adhesive according to  claim 1 , wherein the polyisobutylenes are at least one selected from the group consisting of homopolymers of isobutylene of average molecular weight in the range of 20,000 to 5,000,000 g×mol −1  (determined by gel permeation chromatography), copolymers of isobutylene and a conjugated diene in quantities of 0.3 to 4.5 mol % (relative to said copolymer), terpolymers of isobutylene, divinylbenzene in quantities of 0.01 to 4.5 mol %, and the named conjugated diene.  
     
     
         11 . The adhesive according to  claim 1 , wherein the polyisobutylenes or softening oils are selected from polyisobutylenes, oligomers or polymers of isobutylene or 1-butene, or and modified naphthalene- or paraffin-based oils recovered from petroleum distillation with an average molecular weight in the range of 200 to 20,000 g×mol 31 1  (determined using gel permeation chromatography).  
     
     
         12 . The adhesive according to  claim 1 , wherein said adhesive contains: 
 f) 0 to 80% by weight, preferably 15 to 70% by weight of polyisoprene, polybutadiene, grafted polyisoprene or polybutadiene.    
     
     
         13 . The adhesive according to  claim 1 , wherein said adhesive contains: 
 g) 0 to 50% by weight, preferably 0 to 40% by weight, fillers; and    h) 0 to 25% by weight, preferably 0 to 10% by weight, aromatic resins and/or stabilizers.    
     
     
         14 . The adhesive according to  claim 13 , wherein the fillers are inorganic fillers selected from the group consisting of calcium carbonate, calcium hydroxide, calcium oxide, dolomite, titanium dioxide, zinc oxide, silicon oxide, barium sulfate, manganese dioxide; or the fillers are an organic filler which is preferably carbon black.  
     
     
         15 . The adhesive according to  claim 13 , wherein the stabilizers are selected from the group consisting of epoxides, sterically hindered phenols, amines, thioesters, phosphites, and triazine-, piperidine-, and benzotriazoles.  
     
     
         16 . The adhesive according to  claim 1 , wherein said adhesives contain adhesives comprising at least one of epoxy resins, silicones, polysulfides, polyurethanes, polyureas, or acrylates.